Tools



y 1, 1956 s. DONIGER 2,743,524

TOOLS Filed Aug. 8, 1955 f if INVENTOR. Sunde/ Don ige This invention relates to cutting tools, "and is exemplifi d rein-as a :gouee such as auscd foreaming designs in linoleum o ...otl1er.Inaterials.v p

In its broad aspect, the invention contemplates provision ofian improvedtoolas above characterized/and incorporating aremovable blade.

United St tes Patent More specifically, the invention proposes rigid, non- Y rotatable retention of a removable blade in a rigid handle.

A feature of the invention is to provide an interengagement between the blade and handle which will both prevent longitudinal'slippage and rotational displacement of the blade with respect to the handle in use.

In conjunction with the foregoing object, the invention also provides for readily and conveniently releasing the blade and for extracting the same from the handle without danger of the user cutting himself in performing that operation.

Other objects, advantages and novelty of construction will appear to persons skilled in the art to which the invention appertains, as the description proceeds, both by direct recitation thereof and by implication from the context.

Referring to the accompanying drawing in which like numerals of reference indicate similar parts throughout the several views;

Figure 1 is a perspective view of a cutting tool constructed in accordance with my invention;

Figure 2 is a perspective view of the blade alone;

Figure 3 is a longitudinal sectional view of the said cutting tool, as on line III-III of Fig. 4;

Figure 4 is a cross-sectional view taken on line IV-IV of Fig. 3;

Figure 5 is a longitudinal sectional view of the holding collar alone; and

Figure 6 is a view partly in longitudinal section showing the end portion of the handle alone which cooperates to receive the blade and collar.

In the specific embodiment of the invention illustrated in said drawing, the reference numeral 10 designates the tool handle in general which provides a cylindrical body portion, preferably aluminum, and which is of convenient diameter and length for the user to hold comfortably in one hand. vThe rear end of the handle is equipped with a wooden or other knob 11 held frictionally or otherwise on said body portion and having a rounded exterior for comfortable engagement in the palm of the users hand. One side of this knob is flattened, as at 12, so the tool will not roll when laid on a bench or other surface.

The forward end of said body portion terminates with a stepped construction, the most forward part thereof comprising a slightly tapered or frusto-conical mandrel 13 the smallest diameter of which is at the most forward end of the handle. To the rear of said mandrel, there is a neck 14 coaxial with but of greater diameter than said mandrel and provided with exterior screw-threads 15. To the rear of said threaded neck 14, the diameter in creases abruptly, forming an annular shoulder 16 which 2,743,524 Patented May '1, 1,956

faces toward the. forward end of the handle. Somewhat to ltherear ofsaidvshouldeljgthe peripheral. surface of the handle is shown having a circular ,groove 17 therein whichwaffordsa,gobdfingenfiipwhen the, tool is. inuse.

Remoyably-applied at. the; forward end of the handle body around the. mandrel '13 thereof and, threaded'at 18 to screw onto threaded neck .14 is an elongated collar 1-9-knurledat 20. on itsrexteriorso-as to be-readily-screwed onto-or unscrewed from; said. body by hand without the need QfIElg'WIQIlQhuOI other -1OQl;f,Or that. purpose. The afQRWfidgPQfli-OH of said .collar around, the. mandrel. has, a tapered: hollow or bone therethrough, designated bynumeral 21. Thetaperof saidhollow correpsondsinangularity to the'taperof' theimandrel, but at anyzgiven cross- ;sectional plane has-greater diameter of bore than the diameter thereat :of: the; mandrel. This constructiontherefore provides, ,a frusto=conical )gap 22 between the. .:mandial .andithe collar for receiving the shank 23 of a blade .24 therein. The radial dimension of the gap 22sis such that. sit substantially accommodates the metal thickness :ofathe blade therein under condition of the collar being I "screwed,'honteeagainstushoulder .16. Furthermore, the

taper is such that as thensmalli end' of the mandrel .issinserted at the larger end of the tapered hollow, the radial dimension in the gap (considering the mandrel and collar as coaxial) will be substantially double the thickness of the blade metal. As a matter of fact, however, the initial position of introduction of the mandrel into the hollow will be such that one side of the mandrel will rest against one side of the hollow, and thus temporarily provide a gap opening opposite those engaging sides which will be approximately four times the radial dimension of the blade shank. This has an advantage which will presently appear.

The tool shank 23 is sheet metal curled on a longitudinal axis, so as to be substantially semi-cylindrical,

the inside radius of said shank being substantially equal to the radius of the small end of the mandrel, and the outside radius of said shank being substantially equal to the radius of the small end of the hollow or bore 21 of the collar. As a consequence, the inside and outside radii of the blade shank are diflerent from the respective radii of'the larger end of the mandrel and larger end of the bore of the collar. The metal of said shank is, however, resilient, and when the collar is screwed home said shank is flexed from its normal semi-cylindrical shape to a tapered condition and thereby obtains a very secure frictional gripping within the frusto-conical gap. The resilient deformation of the blade shank also operates to' exert a binding reaction on said collar, and restrains said collar from unscrewing inadvertently.

A positive lock is provided between the blade and the collar, to both limit inward position to which the blade may be pushed and to prevent the blade from rotating while the tool is in use. As here shown, a lip or lug 25 is stamped from the metal of the blade shank at, the crest of its semi-cylindrical curvature. A slot 26 of appropriate dimensions to receive said lug is cut radially in the forward end of collar 19, and in assembling the blade with the handle, the blade shank is inserted into the collar and the lug caused to enter said slot. The collar is pushed inward to engage the threads 18 thereof with the threads 15 of the handle body. Then, as the collar is rotated, it is pulled by the interengaging threads toward and into end abutment with shoulder 16, and while this transpires, the blade shank is spread and obtains the aforementioned frictional gripping and binding reaction which maintains the tool assembled for use and the blade locked against inadvertent rotation.

I claim:

1. A tool comprising a handle body having a mandrel 3 at its forward end and screw threads to the rear of said mandrel, a collar having threads for screwing onto the threads of said body and having a hollow for receiving said mandrel, said hollow being larger than said mandrel and receiving the mandrel loosely therein, and a blade smaller end forwardly whereby a blade shank may be retained in said hollow by virtue of contraction toward the forward end of the hollow in which retained.

3. A tool comprising a handle body having a mandrel at its forward end and screw threads to the rear of said mandrel, a collar having threads for screwing onto the threads of said body and having a hollow for receiving said mandrel, said hollow being larger than said mandrel and both being correspondingly frusto-conical and when assembled providing a frusto-conical gap therebetween, and a blade having a normally semi-cylindrical shank, said shank being resiliently deformable to conform to the frusto-conical shape of said gap.

4. A tool comprising a handle body having a mandrel at its forward end and screw threads to the rear of said mandrel, a collar having a slot in the forward end thereof and having threads at its rear for screwing onto the threads of said body and having a hollow for receiving said mandrel, said hollow being larger than said mandrel and receiving the mandrel loosely therein, and a blade having a shank engageable between said collar and mandrel, said shank having a lug engageable in said slot.

5. A tool comprising a handle body having a mandrel at its forward endand screw threads to the rear of said mandrel, a collar having threads for screwing onto the threads of said body and having a hollow for receiving said mandrel, said hollow being larger than said mandrel and receiving the mandrel loosely therein, and a blade having a shank insertable and deformable between said collar and mandrel and having frictional and gripping and binding reaction with said collar and mandrel.

References Cited in the file of this patent UNITED STATES PATENTS 

